Can't send emails on Outlook

Hi Mike Nolan

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I understand how frustrating it is when Outlook suddenly stops sending emails, especially when receiving still works. Have you already tried the Q&A Assist suggestions? In addition, please try to check SMTP authentication is enabled:

Some providers reject sending if SMTP authentication is disabled, even if receiving still works. In Classic Outlook:

1. Go to “File” > “Account Settings” > “Account Settings”
2. Select your BigPond account > “Change” > “More Settings”
3. Open the “Outgoing Server” tab
4. Check “My outgoing server (SMTP) requires authentication”
   • Select “Use same settings as my incoming mail server”
5. Click OK, then Next, then Finish
6. Send a small test email (no attachment)

Please feel free to let me know how it goes and thank you for your understanding.

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Error 0x800CCC69 with server response 550 5.7.1 comes from the mail server and usually indicates the outgoing message was rejected by the provider (for example, policy, authentication, or spam-related reasons), not a local Outlook bug.

Work through these checks in classic Outlook:

1. Confirm Outlook is online and connected
   • Look at the status bar at the bottom of Outlook. If it shows Disconnected, Working Offline, or Trying to connect…, Outlook cannot reach the server.
   • Go to the Send/Receive tab on the ribbon and select Work Offline once to toggle back online.
   • Try Send/Receive again.
2. Verify internet connectivity
   • Open a browser (Microsoft Edge or Google Chrome).
   • Browse to http://www.microsoft.com or http://www.bing.com.
   • If these do not load, resolve the network issue first using the guidance in Fix network connection issues in Windows.
3. Check for oversized or stuck messages
   • In Outlook, open the Outbox folder.
   • Look for messages with large attachments (typically over 20 MB). Some providers reject large messages and can then block subsequent sends.
   • Open the oldest stuck message, remove large attachments, or replace them with a link, then send again. For more details, see Reduce attachment size to send large files with Outlook.
4. Confirm password and account settings
   • If the password for the BigPond account was changed on the provider’s website, update the same password in Outlook. See Reset a forgotten Microsoft account password for general password-reset guidance.
   • After confirming the password, send a small test message (no attachment) to verify.
5. Check antivirus or security software
   • Some antivirus products scan outgoing mail and can block sending if they detect an issue.
   • If the product shows any email-related alerts, follow its steps to clean or unblock email. If needed, contact the antivirus vendor’s help desk.
6. Repair Outlook and the mail profile if needed
   • If Outlook continues to fail sending even with correct settings and connectivity, repair the Outlook installation using the steps in Repair an Office application.
   • If that does not help, repair or recreate the Outlook profile as described in Fix your Outlook email connection by repairing your profile.
7. Test Outlook in safe mode
   • Press the Windows key, type outlook.exe /safe, and press Enter.
   • In safe mode, try sending a test email. If it works, an add-in may be interfering. In that case, creating a new Outlook profile (see Create an Outlook profile) and disabling problematic add-ins can resolve the issue.

If, after these steps, sending still fails with 550 5.7.1, contact the BigPond/Telstra email support team with the exact error text, as the server-side policy or authentication configuration for the account likely needs adjustment on their side.

References:

• I can't send or receive messages in Outlook